Since workers at a subsidiary of the Kazakh state energy company clashed with police in the west of the former Soviet state in December, the authorities in Kazakhstan have been extremely sensitive about wage disputes with workers. At least 16 people died in the clashes, which spread to a nearby village, damaging Kazakhstan’s reputation for stability and infuriating Kazakh President Nursultan Nazarbayev who has been in power since independence from the Soviet Union in 1991.

A series of wage disputes have since been resolved quickly with little or no media attention.

The dispute at the Annensky mine, which started on Friday when the miners refused to return to the surface after the end of their shift, had been particularly sensitive as local media reported that around 300 other miners had joined the group.